The aim of this work is to provide a fuller spectrum of information in a single source on enzyme-catalyzed reactions than is currently available in any published reference work or as part of any Internet database. The Enzyme Reference: A Comprehensive Guidebook to Enzyme Nomenclature, Reactions, and Methods includes 20,000 review articles and seminal research papers. Additionally, it provides a novel treatment of so-called ATPase and GTPase reactions to account for the noncovalent substratelike and productlike states of molecular motors, elongation factors, transporters, DNA helicases, G-reulatory proteins, and other energases.